// 文字ストリームの階層 java.lang.Object | +--java.io.Writer | |--BufferedWriter | |--CharArrayWriter | |--FilterWriter | |--OutputStreamWriter | | |--FileWriter | |--PipedWriter | |--PrintWriter | |--StringWriter +--java.io.Reader |--BufferedReader |--CharArrayReader |--FilterReader |--InputStreamReader | |--FileReader |--PipedReader |--StringReader